MPs have been told ministers are "wilfully refusing to comply" with a binding order from MPs to hand over the Brexit legal advice as they began a debate on whether the government was in contempt of parliament.
But they were warned to "exercise caution” in demanding to see confidential legal advice, as it would set a precedent that could harm national security and put troops in harm’s way.
Shadow Brexit secretary Sir Keir Starmer, moving the "extremely important" contempt motion, said: “The government is refusing to comply with a binding order of the house - and that is contempt.”
The Government faces censure for refusing to hand over the advice demanded by the House of Commons in a motion last month.
READ MORE: Brexit: Government faces contempt of parliament vote over legal advice
Attorney General Geoffrey Cox insisted the Government has "gone out of its way" to satisfy Parliament's motion calling for the release of the full legal advice on the Brexit deal.
In a letter to Speaker John Bercow he said the motion passed on November 13 calling for the publication of the advice was "extremely vague".
MPs will vote on whether ministers are in contempt and demand a fresh order to publish the "final and full legal advice" provided by the Attorney General to Cabinet.
The dispute over whether Mr Cox's advice should be published threatened to overshadow the start of a marathon Commons debate on the deal which will be opened by Mrs May on Tuesday ahead of the crunch vote on December 11.
Sir Keir said the Government has ignored Opposition motions "for months", adding this tactic has "got them into very deep water indeed".
Sir Keir, addressing the Government amendment which asks a committee to examine claims that ministers are in contempt of Parliament over the issue, said: "There is nothing to refer - a binding order was made and the Government is refusing to comply with it.
"The reality is yet again, by its amendment, the Government is simply playing for time in the hope that this ends up in the long grass until the crucial vote is long gone."
Commons leader Andrea Leadsom responded to the contempt motion by warning MPs that agreeing to their demand would be "irresponsible"
"It would mean releasing information with no method for the House itself to review or assess the information in question before its release into the full domain,” Ms Leadsom said.
She added that it could stop Government lawyers from giving legal advice in the future and "would seriously compromise good government".
The Commons Leader also criticised Labour's use of the 'Humble Address' procedure to try and force the Government's hand, calling it a "blunt instrument" and "arcane".
She said today's motion is not "in the public interest" and it risked breaking a "fundamental principle of the rule of law".
"What we break now, it may be very difficult to fix later", she added.
READ MORE: Brexit: Tories fear being tarred as ‘chaos merchants’ – Paris Gourtsoyannis
Tory grandee Ken Clarke intervened to ask Ms Leadsom if the advice could be provided to opposition MPs under privy council terms.
Ms Leadsom responded rejected the idea, however, telling MPs: "He wants all legal advice to be put into the public domain without any attempt at protecting the national interest."
At the meeting of Cabinet on Tuesday morning, Theresa May insisted that "candid" legal advice given to ministers should remain confidential.
The Prime Minister told Cabinet it was a "long-standing convention" that "neither the fact nor the content of law officers' advice is shared outside Government without their consent".